\Header{corClasses}{Correlation Structure Classes}
\alias{corIdent}{corClasses}
\keyword{models}{corClasses}
\begin{Description}\relax
Standard classes of correlation structures (\code{corStruct})
available in the \code{nlme} library.\end{Description}
\begin{Value}
Available standard classes:
\begin{ldescription}
\item[\code{corAR1}] autoregressive process of order 1.
\item[\code{corARMA}] autoregressive moving average process, with arbitrary
orders for the autoregressive and moving average components.
\item[\code{corCAR1}] continuous autoregressive process (AR(1) process for a
continuous time covariate).
\item[\code{corCompSymm}] compound symmetry structure corresponding to a
constant correlation.
\item[\code{corExp}] exponential spatial correlation.
\item[\code{corGaus}] Gaussian spatial correlation.
\item[\code{corLin}] linear spatial correlation.
\item[\code{corRatio}] Rational quadratics spatial correlation.
\item[\code{corSpher}] spherical spatial correlation.
\item[\code{corSymm}] general correlation matrix, with no additional
structure.
\end{ldescription}
\end{Value}
\begin{Note}\relax
Users may define their own \code{corStruct} classes by specifying a
\code{constructor} function and, at a minimum, methods for the
functions \code{corMatrix} and \code{coef}. For
examples of these functions, see the methods for classes \code{corSymm}
and \code{corAR1}.\end{Note}
\begin{Author}\relax
Jose Pinheiro \email{Jose.Pinheiro@pharma.novartis.com} and Douglas Bates \email{bates@stat.wisc.edu}\end{Author}
\begin{SeeAlso}\relax
\code{\Link{corAR1}}, \code{\Link{corARMA}},
\code{\Link{corCAR1}}, \code{\Link{corCompSymm}},
\code{\Link{corExp}}, \code{\Link{corGaus}}, \code{\Link{corLin}},
\code{\Link{corRatio}}, \code{\Link{corSpher}}, \code{\Link{corSymm}}\end{SeeAlso}

